Abstract: Yongji Irrigation District was selected to investigate the correlation between pH,water contents and nutrients of saline-alkali soils as the investigative area in arid irrigation districts.The concentrations of pH,soil moisture content (SMC),organic matter (OM),total nitrogen (TN),Zn and Cu in soil profiles under 3 land-use patterns were measured to analyze the distribution of soil pH and the fitting equations.The results showed that the mean pH was 9.13;the soil moisture contents ranged from 2.96% to 31.35%;the average mean of OM and TN was 11.30 and 0.49 g·kg^-1,respectively;the mean value of Zn and Cu was 107.20 and 32.78 mg·kg^-1,1.9 and 1.7 times higher than the background value respectively.There were very significant differences in soil pH under 3 land-use patterns (P<0.001),decreasing in the order of wasteland > cropland > forestland,but there was similar among soil profiles (P>0.05).The variation in soil pH was primarily affected the variation in TN for 3 land-use patterns and the regression equation was Y_pH=9.336-0.409 X_TN(P=0.001);for topsoil (0-40 cm),the content of Cu suggested influences of soil pH,and the regression equation was Y_pH=0.018 X_Cu+8.523(P=0.003).So in our study,on the one hand soil basification resulted in the short of soil nutrients.On the other hand,agricultural activity such as fertilization may lower the pH in topsoil,but the accumulation of microelement caused by the activity significantly increased soil pH.Therefore,increasing the agriculture inputs should pay more attention to apply the pesticides and fertilizers scientifically and reasonably,at the same time.

Key words: Yongji Irrigation District, soil pH, soil water, soil nutrients, soil profiles, land-use patterns, correlation